The aseptic filling system is a system according to which a container such as a bottle in which a drink is to be filled as well the drink are sterilized and the drink is filled in the sterilized container in a sterilized environment. As a method for sterilizing a container is widely used a method of sterilizing a container by using hydrogen peroxide aqueous solution or hydrogen peroxide mist and thereafter washing the container by using sterilized water or hot air. In the aseptic filling system, amounts of sterilizing agent and sterilized water for washing are determined depending upon a line construction of the aseptic filling system. As the line speed is increased, amounts of supply of the sterilizing agent and the sterilized water to the line per unit time are also increased which causes the problems that initial cost and running cost are increased, the sterilizing apparatus and space for installing such apparatus become larger, and load to the environment increases. In particular, in a case where a container is sterilized by using hydrogen peroxide mist in the aseptic filling system, it is necessary to heat and thereby vaporize hydrogen peroxide aqueous solution and then condense the vaporized hydrogen peroxide to produce hydrogen peroxide mist and, for this purpose, an apparatus for generating mist must be installed in the system. This not only increases the size of the system but also requires, for example, about 8 seconds for sterilizing the inner surface of a single PET bottle of 500 ml with resulting increase in the line speed and requirement for two or more turrets for sterilization in the sterilizing system in which a large number of PET bottles are sterilized while they are moved on these turrets. The reason for requiring about 8 seconds for sterilizing the inner surface of a single PET bottle is that, as the PET bottle becomes thinner, projections and depressions in a reinforcing bead of the bottle, for example, increase for maintaining or reinforcing the configuration of the bottle and hence it requires sufficient time for each minute droplet of hydrogen peroxide mist which is an aggregate of minute droplets to scatter to reach all surfaces of such projections and depression and to be deposited on the inner surface of the bottle uniformly. Patent Literature 1 discloses a method and a device for sterilizing a container according to which a sterilizing agent which is turned to mist by a mist generation device is mixed with hot air and supplied to inside of a bottle to sterilize the bottle, then sterilized air is blown into the bottle to exhaust the mist to the outside and then a washing liquid is supplied to the inside of the bottle to wash the bottle. This method however requires the mist generation device and an air wash device for supplying sterilized air and, as a result, the sterilizing apparatus becomes large. Besides, sterilization must be continued until minute droplets of the sterilizing agent mist reach all of the surfaces of projections and depressions of the bottle and, as a result, this method cannot settle the problem of the prior art methods that a long period of time is required for sterilization.